The KiCAD files for the FortyTwo UNO can be found at https://github.com/fortytwosystems/Uno. Clone the repo and open in KiCAD 5.99 (nightly build of 6).
The KiCAD files for the FortyTwo MEGA can be found at https://github.com/fortytwosystems/Mega. Clone the repo and open in KiCAD 5.99 (nightly build of 6).
A quick rundown of the main components shown in the schematics:
ATSAMC21G (U1) - the main processor on the board. Connected to a 32.768 kHz crystal for accurate timing.
NCP1117 (U5) - 5V voltage regulator, linear. The lower the voltage (down to ~7V) applied, the less heat will be generated by this part. Do not apply more than 20V, however the reccomended maximum is 12V.
LP2985 (U6) - 3.3V voltage regulator, linear. Rated for 150mA.
LMV358 (U2) - dual comparator. Half is used to determine whether USB or the barrel jack should supply power, half is used as a buffer on the pin 13 LED.
FT231XQ (U4) - FTDI chip. Used to convert serial to USB for communication with a computer.